1. Field of Invention
The invention relates to a manufacturing method of a light-emitting diode (LED) apparatus.
2. Related Art
A light-emitting diode (LED) apparatus is a light-emitting device made of semiconductor material. It pertains to a cold light emitting element and has the advantages of low power consumption, long lifetime and fast response speed. In addition, the LED apparatus has small size so that it can be used to manufacture fine device or array-type device. Therefore, the applications of the LED apparatus can be spread into the indicator of a computer or a house appliance product, the backlight source of a LCD device, and the light of traffic sign or vehicle.
To increase the lighting efficiency of the LED apparatus, a metal reflective substrate is added to a LED device for reflecting light, thereby increasing the lighting efficiency. However, this architecture of the LED apparatus still has some problems to be solved.
FIG. 1 shows a LED apparatus disclosed in a Taiwan Patent number 544,958. The LED apparatus includes a metal reflective substrate 801 and a multilayer disposed on the metal reflective substrate 801. The multilayer includes a first reaction layer 802, a transparent adhering layer 803, a second reaction layer 804, a transparent conductive layer 805, a first contact layer 806, a p-type epitaxial layer 807, a light-emitting layer 808, an n-type epitaxial layer 809 and a second contact layer 810 in sequence. In addition, electrodes 811 and 812 are respectively formed on the second contact layer 810 and the transparent conductive layer 805.
The transparent adhering layer 803 attaches the first reaction layer 802 and the second reaction layer 804 and also connects the metal reflective substrate 801 to the first reaction layer 802. However, since the transparent adhering layer 803 is made of a plastic material, the heat generated by the LED apparatus cannot be transferred to the metal reflective substrate 801 and then be dissipated. Thus, the heat is accumulated inside the LED apparatus, resulting in the decrease of the efficiency.
Moreover, during the manufacturing processes, the metal reflective substrate 801 and the multilayer are cut to obtain a plurality of LED apparatuses. However, metal particles may be attached to the side surface of the multilayer in the cutting process, which will increase the current leakage from the multilayer.
FIG. 2 shows a LED apparatus disclosed in a Taiwan Patent number 543,210. A metal bonding layer 901 is provided to connect a LED multilayer 902 and a metal reflective substrate 903. In this case, a high-temperature high-pressure process is needed to connect the metal bonding layer 901 and the metal reflective substrate 903. However, this method will lead to diffusion between the LED multilayer 902 and the metal reflective substrate 903. In addition, regarding to the LED apparatus, the dicing process may also increase the current leakage of the LED multilayer 902.
The above-mentioned conventional LED apparatuses both form the epitaxial multilayer on an epitaxial substrate, and then transfer it onto a glass substrate or a plating substrate. Furthermore, a dicing process is necessary to obtain the desired LED apparatuses. Thus, the conventional manufacturing methods not only need the additional dicing process, but also increase the possibility of attaching the metal particles on the side wall of the multilayer.
Therefore, it is an important subject to provide a manufacturing method of a LED apparatus for solving the above problems and thus increasing the performance thereof.